Air cushion spring suspension



Aug. 12, 1952 R. cAlRNs 2,606,757

AIR CUSHION SPRING SUSPENSION Filed May 8, 1951 INVENTOR ROBERT CA\RNS Patented Aug. 12V, a1952 UNITED"*STATES i OFFICE f 2,606,757'. ,f

f AmA ousmoN SPRING SUSPENSION K lvtob'elr't(Jairlis,` Toronto, ntarioQanada i applicaties May 8, 1951, serial No. 225,154

This inventionv relates to a, spring suspension and Vthe principal objectis to provide such a suspension in which the spring actionis effectively cushioned with air to absorb heavier shocks and impacts without requiring excessive spring stiffness to enable the use ofa spring element capable in itself of absorbingand cushioning the lighter pressures and impacts. 1

Afurther object is to enablespring recovery to be retarded under air-'pressure following impact to facilitateA dissipation of impact force.

Still a further object is `to provide aspring suspension as `aforesaid of relatively simple and inexpensive construction 4to replace standard spring suspension and shock absorber units on motor vehicles.

The principal feature of the invention resides in suspending a load-carrying leaf spring element from within a` channel to ilex between an unloaded position arching above the channel walls and a loaded position adjacent Ythe channel bottom, the spring being formed to engage the channel wallsmwhen moving into the channel in snug edge sealing relation to dene'with the channel a, compressionV chamber having restricted Teommunication with the atmosphere beneath the ends of the spring.

A further feature consists in combiningwith the spring element a resilient edge sealing member to maintain pressure in the compression chamber against escape past the edges of the spring.

These and other objects and features will become apparent with reference to the accompanying drawings in which:

Figure l is an elevational View of an automobile partly broken away depicting the application of the present invention.

Figure 2 is an enlarged vertical cross sectional view of the suspension in normal relatively lightly loaded position.

Figure 3 is a view similar to Figure 2 but showing the spring element depressed under a load.

Figure 4 is an enlarged elevational detail and Figure 5 is an enlarged transverse cross sectional detail.

With reference to the drawings, the automobile I is shown as having a main frame bar 2 from which the axle 3 carrying the wheels 4 is suspended.

The device forming the spring suspension is shown in detail in Figures 2 to 5 and comprises a spring element generally designated as 5 operating in a channel 6 secured to the frame bar 2 by the bolts 'I. The spring element 5 is made 5 Claims. (c1. 267-31) up-ofa plurality of leaves 8 accordingto the desired spring stiffness bolted to theA main spring element 9 which is formed with angularly bent ends I0 sliding on the base of theA channel 6 beneath the suspension brackets I I.

g The Spring element 9 is free to slide under ilexing as guided by the channel base and brackets I I, and both the spring 9 and brackets are shown provided with wear shoes I2 and. I3 respectively. The spring 9 and channel 6 are ground for maximum tightness, and it will be seen that the spring in moving into the channel from the position of Figure 2 to the position of Figure 3y defines a compression vchamben I5 which progressively diminishing under inward spring movement. Y Since the spring 9 is in tight edgesealingfcon tact with the channel walls I6 the escape oi air is restricted substantially -entirely toV iiowv out beneath the spring ends I0. It will be appreciated that the compressive force on the spring acts to urge lthese ends I0 .against thechannelbottom whilev the air pressure within the chamber I5 actsto urge :the'ends I0 away from the channel bottom topermit` escape of the air. i f v :There is thus a Vself-regulating effect produced with pressures in the chamber I5 being increased automatically tocushion larger impact Yforces "on the spring. Y i 1 Y Air" escaping from beneath` the spring ends ill is Vfree toescape through openings I'I whichare` in communication with the atmosphere.

In the particular illustration the load is imparted to the spring element 5 through the spring seat bracket I8 which is secured to the spring element and carries the axle 3.

To further increase the seal of the compression chamber I5 at the edges of the spring element a resilient or rubber material I9 is utilized. In the illustration this element I9 is in the form of a iiat wiper element extending the full Width` of the spring 9, and it will be appreciated that pressure of the chamber will expand it into sealing engagement with the channel walls I 6 under inward spring movement.

If desired rubber may also be bonded to the edges of the spring I9 to resiliently engage the channel Walls. The channel is preferably ribbed for rigidity and is shown with a longitudinal rib 20 and vertical stiffening ribs 2 I.

In the normal position of Figure 2 with the spring unloaded it will be appreciated that the entire spring element 5 projects below the wall I6 of the channel, providing for free entry of air therein. As the spring moves inwardly it is guided by the chamfered edges 22 of the walls I6 into the channel to form the expansion chamber I5 which provides the cushioning effect described. When impact is completed the spring moves outwardly which in turn creates a reduced pressure in the chamber I5 which can only be normalized through introductionof air through restricted flow between the spring ends l0 and the channel base, permitting relatively slow outward spring movement. This outward retardation of spring movement effectively damps and facilitates dissipation of the reactive spring thrust.

If desired one of the ends I9 of the spring maybe anchored but it has been found that the spring maintains a centralized position with' .both ends freely sliding in unison under spring movement.

With the air cushioning effect obtained on inward spring movement and the retardation of outward spring movement it will be appreciated Y that the single spring arrangement providesI both for spring suspension and shock absorption.

"Since'the larger or ultimateimpact loads are supported or absorbed byan air cushion in the chamber I5, it will be appreciated that the spring element 5 itself may be made of the requisite stiffness to give the initial spring ilexibility without undesirably lowering its load capacity in ultimateimpact. This springmay .be lubricated through suitable grease ttings 23 and the construction of the suspension brackets Ii and the other structural details may be altered as desired without tion. f

" What I claimas my invention is:

1."A suspension spring construction, comprising anfinverted channel having parallel depending'side Walls, and an arched spring element supported at the ends within the channel and ilex ing between said walls in edge wiping contact therewith to define a variable air chamber within saidvchannel having restricted communication with the atmosphere above the ends of said spring.v 2 A suspension spring assembly, comprising an inverted channel having paralleldepending side walls, a broad leaf spring element supported by the ends Within said channeljand flexing in snugA edge wiping contact with said parallel walls to dene a variable air chamber within said channel, the ends of said spring sliding freely in said channel andiseparating under pressure in said chamberfrom said channel to permit restricted departing from the scope of the invenair ow between said channel and spring ends, said channel at the ends of said spring being open to the atmosphere, and a spring seat bracket secured to said spring element.

3. A device as claimed in claim 2 in which said spring element carries a flexible material wiping on said channel walls at the edges of said spring element to form an edge air seal.

4. A flexible spring suspension, comprising an inverted channel having depending parallel walls, a pair of brackets forming spaced opposed support shelves at the ends of the channel bottom. a leaf spring element arched between said brackets and iiexing'in snug edge wiping contact with said parallel walls to denne a variable air chamber within said channel and having angularly turnedv ends sliding on said channel bottom in close sliding proximity with the shelves and affording upon separating under air pressure in said chamber from said channel bottom against said shelves, restricted air ow passages between said ends and channel bottom, said channel being open to the atmosphere at the ends ofsaid spring',l and a spring seat bracket secured to said spring element. l

5. A device as claimed in claim A4v in whichvsaid spring element is formed to arch below said walls with load removed and said walls have their inner free edges chamfered to guide ysaid spring therebetween in centralized movement into'said channel under loading, said spring carrying la flexible material exposed at the edges thereof to engage said walls in resilient wiping contact unde spring movement into and out of said channe ROBERT CAIRNS.

REFERENCES `CITED The following references are of record in the France Apr. 29, 1929 

